Naphthazarin intermediate dye and process of making same.



RENE noun, or MANNHEIM, GERMANY, ASSIGN'OR TO THE BADISOHE" ANILIN AND SODA FABR-IK, or LUDWIGSHAFEN, GERMANY.

NAPHTHAZARIN INTERMEDIATE DYE AND PROCESS OF MAKING SAME.

SPECIEFECATION forming part of Letters Patent No. 631,614, dated. August 22, 1899.

To all whom it may concern} Be it it nown that I, RENE BOH N, doctor of philosophy, a citizen of the Swiss Republic, residing at Mannheim, in the Grand Duehy of Baden and Empire of Germany, have invented new and useful Improvements in the ,Manufacture of a New Coloring-Matter, of

' the German patent, No. 76,922, published on the 21st of August, 1894, in the following terms: Its solution in concentrated sulfuric acid (containing about ninety-five per cent. H 80 is brown. In dilute sulfuric acid it dissolvcs'with a pure blue color. This color is not appreciably changed on adding causticsoda lye; but if an excess of hydrochloric acid beadded to the dilute sulfuric-acid so lutionthe color turns to a greenish brown. W'hen isolated, this naphthazarin intermediate product is a violet-powder, possessing a metallic luster, slightly soluble in water and giving a blue solution, which is not changed in color by the addition of sodium carbonate or of a caustic-soda; lye. I In the presence of.

a little hydrochloric acid it dissolves readilywitha pure blue color. If the solution in dilute sulfuric acid be boiled, the blue color changes to red and on cooling naphthazariu" separates out.

g It is this-naphthazarin'intermediate product, which can be obtained as described from 1. 5-dinitro-naphthalene,which constitutes the initial material for my invention. My present invention relates to. the discovery that on reduction this intermediate product is converted into-anew product, which apparently stands to it in the relation of a leuco-compound and which can be-used-dircctly in dyeing on chrome-mordints. The] new product is but little soluble in water and let color.

I Application filed August 10, 1898. Serial No. 688,275. (No specimens.)

can therefore be readily isolated. When dyeing, the new product can either be used "directly or in 'the form of its bisulfite compound. The shades obtainedareofia greener cast than those yielded by naphthazarin. They are very fast to light.

The following example will serve to illustrate the nature of the invention andthe manner in which it can be carried into prac'-. tical effectand my new product ob.tained.'

The parts are by weight.

Prepare a naphthazarin melt in the usualway by heating 1.5-di-nitro-naphthalene yvith concentrated or fuming sulfuric acid with the addition of a suitable reducing agent. Pour five hundred (500) parts thereof (correspondin g to fifteen (15) parts naphthazarin) int-p two thousand five hundred (2,500) parts of water. Filter the solution. Next add .a' solution :of

forty (as)- parts tin salt (stannous chlorid) in two hundred (200) parts of hydrochloric acid, (containing about thirty-two per cent. real H01.) The deep-bluc-colored solution changes first to red, and the mixture finally becomes almost colorless, while the newproduct sepa' rates out in fine needles almost colorless. Filter, wash with water, and either dry or preferably preserve for use in the form of paste.

Instead of taking the naphthazariu melt itself in the above example, the isolated intermediate product, say, in the form-of its sodium salt can be submittedto thereduction" process;

Instead of the hydrochloric-acid solutionof stannous chlorid, other reducing agents can be used.

In the moist state the new product presentsthe, appearance of almost colorless crystals. When dry, the crystals appear bluish. It is soluble in sodium carbonate, giving ared-vio- Its solution in cau'sticsodalye is red and becomes blue violet in contact with the air, and a precipitate havinga metallic luster separates out. It is but slightly solu;

ble in water; but on boiling a somewhat bluish'solution is obtained. Its solution in concentrated sulfuric acid is red, turning on heating. Now whatI claim isbrown l. The new coloring-matter. which can be obtained from the naphthazarin intermediate naphthazarin intermediate product, as here product, as hereinbefore defined, by reducinbefore defined, to the action of a reducing tion and which is soluble in caustic-soda lye agent, substantially as described giving a red solution which becomes blue vio- In testimony whereof I have hereunto set 5 let on exposure to airwhile depositinga premy hand in the presence of two subscribing I5 cipitate, and which also yields a red solution witnesses.

in cold concentrated sulfuric acid turning RENE BOIIN. brown on heatinmv Witnesses:

2. The process for the production of a new GUSTAV L. LIOHTENBERGER,

m coloring-matter consisting in subjecting the ADOLPH REUTLINGER; 

